Because of the numerous emission control components in today's vehicles, along with their projected increase over the next decade, it has been found necessary to effect government regulations requiring a visual indication, e.g., lights on the dashboard of the vehicle, to indicate the need to perform each important servicing requirement for these components. Since different emission control components have different servicing requirements, it is necessary to provide these signals at different mileage intervals, for example one component might require maintenance every five thousand miles, while another component may require maintenance only at fifty thousand mile intervals. It is also desirable that the individual indicating systems be resettable so that after the maintenance has been performed on the vehicle, the indicating system will again begin counting vehicle travel for the second maintenance event.
With this background it has been found advantageous to employ a counting mechanism, similar to that provided in conventional vehicle odometers to actuate various types of switch mechanisms. However, known designs employing these combined odometers and switches have thus far not been found completely acceptable because of limitations on the mileage intervals, the inability to reset each interval function independently of the others, and the extreme complexity of the units making them difficult and expensive to manufacture.
It is the primary object of the present invention to ameliorate the problems noted above in counting mechanisms that provide one or more signals after the predetermined mileage intervals to indicate the need for maintenance.